In this part of the electrolysis of aqueous solutions lab, you see the electrolysis of two aqueous sodium sulfate solutions. One of the solutions contains only dissolved sodium sulfate. Bromthymol blue (BTB) has been added to the other solution. You will also see what happens when the electrolysis apparatus is placed in distilled water.

After you have added the electolysis apparatus to each drop, you will be able to see what is happening in the solution to cause the observable change.